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Gen 1 A/C issue

Discussion in 'Generation 1 Prius Discussion' started by bigblock67, May 3, 2015.

  1. bigblock67

    bigblock67 433K with new cells

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    AC light flashes as it disengages clutch at any given time. Very cold when it stays engaged. AC gauge shows around 36 lb on the low side. High side fluctuates around 250 to 300 lbs. Thinkin may have bad relay?? This is an 02 with 326k miles
     
    #1 bigblock67, May 3, 2015
    Last edited by a moderator: May 3, 2015
  2. ChapmanF

    ChapmanF Senior Member

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    What are the codes? You don't need any special scanner or tools to pull the A/C codes on a Gen 1.

    -Chap
     
  3. bigblock67

    bigblock67 433K with new cells

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    I didn't check for codes. The AC button has a light that flashes that shuts off AC clutch. Is there a code for this issue?
    Thanks for reply
    Don
     
  4. ChapmanF

    ChapmanF Senior Member

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    Yes. Start with the ignition off and the fan switch turned to off.

    Turn the key ON, then within 5 seconds press A/C 3 times then turn the fan switch to AUTO.

    You'll get several slow blinks of all the HVAC LEDs, and then pattern blinks on the A/C button. If you really have no codes it's just a steady fast blink. Otherwise it blinks two digit code patterns. There are a ton of threads here you can search for more info.

    Finding out what your problem really is can influence the cost of fixing it, in the range from one dollar to several thousand. That's why some people with money to burn don't bother finding out.

    -Chap
     
  5. bigblock67

    bigblock67 433K with new cells

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    OK did that and steady fast blink. I added some 135 last night and it seems to work longer but finally kicks off. What are the pressures on high and low side? Is there a pressure switch?
    Don
     
  6. ChapmanF

    ChapmanF Senior Member

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    The high-pressure and low-pressure switches are wired together, so the computer will shut stuff off if the pressure gets either too low or too high, but it shows the same code 23 either way because it doesn't have separate wiring to tell which switch tripped. If it shuts down because it detects clutch slippage, that's code 22. Those are probably the most likely two culprits; all our Gen 1 clutches are getting old so code 22 is a familiar sight.

    Since you didn't see any code, did you try to pull them right soon after it shut off and blinked, or some other time? I would try again.

    If you have code 22, check out this thread, but be sure you read all the way past the longwinded whole-clutch replacement instructions until you see how to readjust using the shim kit, which will cost you a buck and possibly give you another 326k miles.

    If you have code 23, sign in on techinfo.toyota.com for all the information you need on tracking down what the pressures need to be and under what exact test conditions, how to tell a real pressure problem from a switch or wiring problem, etc. If it turns out that you need to add refrigerant, read carefully the procedure for determining the correct charge, because the subcooling condenser makes it a little different from what you might be used to.

    Also, if you have a 22 but you find the clutch travel is not out of spec, then the 22 might result from a wiring problem to the slippage sensor, etc., and techinfo will also have the steps for sorting that out.

    -Chap
     
  7. bigblock67

    bigblock67 433K with new cells

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    I pulled codes when motor was cold. Will try hot. Glad to know that a code will eliminate chasing what's not there.
    Great help
     
  8. bigblock67

    bigblock67 433K with new cells

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    No change under any circumstance. steady fast blinking.